1. Field of the Invention
The present invention relates to a vertical nano-sized transistor and a method for manufacturing the same. More specifically, the present invention relates to a vertical nano-sized transistor using carbon nanotubes capable of achieving high-density, or tera-bit scale, integration and a method for manufacturing the same.
2. Description of the Related Art
A switching device fabricated using a conventional silicon substrate is generally constructed such that an impurity diffusion region, an isolation region and a channel region are horizontally connected on the silicon substrate. An integrated circuit consisting of multiple switching devices is constructed such that the individual switching devices are horizontally arranged to be highly integrated. A problem arising from forming an impurity diffusion region and an isolation region on a silicon substrate is that there are limits in processing precision and integration. A result of the limitations imposed by forming an impurity diffusion region and an isolation region on a silicon substrate is the difficulty to decrease the size of the switching device.
A metal oxide semiconductor field effect transistor (MOSFET) is one of the most typically used fine switching devices. The area of a 256 Mega DRAM having a minimum pattern size of 0.25 μm is approximately 0.72 μm2; the area of a 1 Giga DRAM having a minimum pattern size of 0.18 μm is approximately 0.32 μm2; the area of a 4 Giga DRAM having a minimum pattern size of 0.13 μm is approximately 0.18 μm2, and the area of a 16 Giga DRAM having a minimum pattern size of 0.1 μm is approximately 0.1 μm2.
In order to overcome problems in miniaturizing conventional switching devices, a switching device using carbon nanotubes has been proposed. However, the proposed device still has a horizontal structure similar to that of other conventional switching devices making it quite difficult to control the individual carbon nanotubes.
As a result, it is difficult to achieve high-density integration of switching devices using carbon nanotubes.